Discharging device for centrifugal machines



Sept. 5, 1933. T MEER 1,925,121

DISCHARGING DEVICE FOR CENTRIFUGAL MACHINES Filed Jan. 12. 1932 2 Sheets-Sheet 1 J6 Fig.1. '13

INVENTOR 0113500 2727' Hear B Y .42. fwwm ATTORNEYS Sept. 5, 1933.

G. TER MEER v DISCHARGI ENTRIEUGAL MACHINES 2 Sheets-Shet' 2 Filed Jan. 12, 1932 INVENTOR 011M011 ierjleer llll 1 Il .ilL r ATTORNEYS' Patented Sept. 5, 1933 UNITED STATES PATENT. OFFICE DISCHARGING DEVICE FOR CENTRIFUGAL MACHINES Gustav ter Meer, Munich, Germany, assignor to Albert T. Otto & Sons, New York, N. Y., a corporation of New York Application January 12, 1932, Serial No. 586,169, and in Germany January 27, 1931 7 Claims. (Cl. 233-46) The invention has reference to centrifugal machines serving for the separation of solids from liquids, for instance sludge from water. Ordinarily, the solids which have been deposited on the inner wall of the centrifuge bowl by the action of centrifugal force, are removed by a knife-like scraper, the so-called scraper knife. A discharging device of this kind is known, in which the scraper knife is attached, by. bolts or similar means, to a holder serving as a guide, said holder being revolvably disposed on a shaft which is eccentric in relation to the centrifuge shaft, the

device being moved towards the inner wall of the revolving centrifuge bowl by a mechanism which However, a discharge device of this description has several draw-backs. One of them resides in the fact that in moving the knife and its holder toward the inner wall of the bowl, the position of the knife relative to the wall of the bowl changes constantly, with the result that the keen edge of the knife soon becomes dull. Thereafter the knife must be pressed against the material to be removed with much'greater force. This places a greater strain on all parts of thedischarge device, principally on the driving motor. It is necessary, for this reason, to take out and regrind the knife at frequent intervals, thereby necessitating undesirable shutdowns which are frequently of long duration. In addition, a discharge device of this known kind requires a knifeholder-arm of comparatively great length, rendering the construction extremely unstable. This condition makes it necessary to materially reduce the speed of the bowl during the scraping action, in order to prevent injury to the discharging device. Slowing down the bowl by means of a brake involves-loss of power, which must be expended defects.

anew after the emptying of the drum.

The object of this invention is to remedy these This is attained in such manner that the knife-holder, which is actuated by a suitable source of power, is disposed on guide-columns,

and is moved up and down against the wall of the bowl in a direction radial to the shaft.

An additional object of the invention is to provide a scraper knife, which extends substantially across the entire length of the bowl, and is so disposed that it can easily be exchanged, by a few manipulations, when the holder is in non-scraping position.

Other details and merits of the invention appear in the following full description and in the drawings, of which V Fig. 1 shows a side elevation, partly in section, of a centrifugal machine.

Fig. 2 shows an end elevation. D

Fig. 3 shows an enlarged end elevation of the scraper device, a part ofthe bowl being shown in section, and

Figs. 4 and 5 are a section and a front-elevation respectively of the scraper knife and its holder, on a larger scale.

1 is a centrifuge bowl, which is keyed to shaft 2. The latter runs in the two bearings 3a and 3b, and carries, on one end, a driving pulley 4. The bowl 1 is surrounded by a housing 5,which consists of an upperand a lower part. An inclined discharge chute 6 projects into the bowl, and is attached to the housing 5 in any suitable manner. A scraper-box 7 projects into the bowl, and has one of its walls formed as a support for the scraper-knife 8 in the form of a thin, hard blade, such as saw-blade steel. At the outside, this scraper box '7 has a cross-rail 9, the ends of which form sliding members 10. The scraper-box thus formed is guided on columns 11 disposed on opposite sides of the centrifuge shaft 2 perpendicular to the horizontal plane of the axis'of the bowl 1. The ends of the guide-columns are bolted to lugs on the housing 5. Upward and downward movement of the scraperbox '7 on said guide columns is effected by a working cylinder 12 located on housing 5, and having therein a piston 13 controlled by a suitable pressure medium, such as compressed air, steam, liquid, or the like. Piston 13 has a piston-rod 14 which is firmly connected tothe cross-rail Q of the 'scraperbox. Whenever the pressure-medium is admitted to the workingcylinder 12 through an opening 15, the piston 13 is forced upwardly, moving scraper-box .7 in a radial direction against the wall of the bowl. By this action, the scraper-knife 8 is pressed against the centrifuged material deposited on said bowl, thereby peeling it off when the bowl is in rotation (see Fig. 2) After the removal of the centrifuged material, the pressure in the cylinder space below the piston 13 is cut off, and the pressure medium is introduced through an opening 16 into the upper part of cylinder 12. The piston 12 is thus forced downwardly, and the'scraperbox 7 returns into its original position, in which it remains until sufficient material has again accumulated on the wall of the bowl.

Due to the factthat scraper-knife 8 approaches the wall of the bowl on a straight course, the cutting angle during the action of removing the deposit remainsnearly constant, from the beginning to the end of the peeling operation. This affords the advantage, that the bevel surface of the scraper-knife, during the scraping,- is constantly being pressed against the revolving layer of material and thus the bevel surface is ground by the material, so that the knife will retain its keen edge regardless of wear.

The scraper knife itself is disposed in a special beam-shaped holder 17 having a U-vshaped crossward the axis of the bowl to form a wedge-shaped recess. Into this recess through the open end thereof may be inserted the scraper knife 8, and

may be held tightly therein by means of a key or wedge 18 (Fig. 4) This wedge 18 has its wedging surfaces converging toward the rear edge of the scraper knife. By means of this arrangement, the pressure applied against the cutting edge of the scraper knife during its peeling operation is transmitted to the wedge 18 and tends to force said wedge further into the recess of the holder 17 and thus tighten the blade.

The wall of the scraper box 7 has a dove-tail groove between spaced walls forming a claw 19 open at its end so that when the scraper box 7 is in its lowermost position, the holder 17 with the knife firmly held therein may be slipped through the lateral opening of the drum into said claw 19, and will be retained therein. No bolts or rivets are required for holding the scraper knife in the holder 17, or for securing the latter in the claw 19. This arrangement has the advantage that the scraper knife 8 with its holder 17 can be taken out of the bowl with ease and expedition while the bowl is in motion, when the scraper box 7 is in its lowermost position, for the purpose of examining and, if necessary, grinding or replacing the knife.

To take the scraper-knife out of its holder 17, it is only necessary to loosen the key 18, by striking it from below with a tool inserted through an opening 21 in the base of the holder 17.

This wedge assembly, in accordance withthe invention, has the advantage that the scraper knife can be adjusted by loosening the wedge 18 and pushing the knife 8 forward the desired amount, thus permitting fullest use of the blade.

According to the invention, the scraper-knife may consist of several parts, so. that only the worn-out portion need be exchanged for a new one. Furthermore, it is possible to interchange the position of the parts. This is important, as the cutting faces, according to experience, wear out quicker at the ends next to the side-walls of the bowl. By exchanging the knife-sections, a more uniform wear of the knife can be obtained than would be possible with a knife made in one piece.

It will be understood that the invention is not restricted to the form of the individual parts shown in the illustrations.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

1. A centrifugal machine for separating solids from liquids, including a separating drum open at one end, a shaft for said drum, a pair of spaced columns symmetrically disposed on opposite sides of said shaft, a cross rail outside of and adjacent to the open end of said drum and having its ends engaging said columns for slidable movement therealong, a fluid actuated piston connected to said cross rail for moving the latter, a member connected to said cross rail, and a scraper connected to one edge of said member at one end thereof.

2. A centrifugal machine for separating solids from liquids, including a separating drum open at one end, a shaft for said drum, a pair of spaced columns symmetrically disposed on opposite sides of said shaft, a crossrail outside of and adjaits ends engaging said columns for slidable movement therealong, a member connected to said cross rail, and a scraper connected to one edge of said member at one end thereof.

3. A device adapted to be used in a centrifugal machine for removing separated solids from said machine, and including a scraper, a U-shaped holder for said scraper, a wedge between said scraper and one arm of said holder, and having the wedging surfaces thereof converging towards the rear edge of the scraper to firmly hold said scraper in position, and a chute for conveying separated solids, and having a recess along one edge at one end thereof for receiving the sides of said holder.

4. A device adapted to be used in a centrifugal machine for removing separated solids from said machine, and including a scraper, a U-shaped holder for said scraper, a wedge between said scraper and an arm of said holder, with the wedging surfaces thereof converging towards the rear edge of the scraper for firmly securing said scraper between the arms of said holder, said holder having a recess at the base thereof to permit the removal or loosening of said wedge, and a chute for conveying the separated solids and having a groove along one edge at one end thereof for receiving said holder.

5. A device adapted to be used in a centrifugal machine for removing separated solids from said machine, and including a scraper, a holder for said scraper having the sides near the base thereof converging from said base, and a chute having a dove-tail recess along one edge into the end of which said holder may be slid, the walls of said recess preventing movement of said holder toward the edge of said scraper.

6. A device adapted to be used in a centrifugal.

machine for removing separated solids from said machine, and including a chute for conveying separated solids, and having a dove-tail recess along one edge thereof, a beam-shaped holder U-shaped in cross-section, and slidable endwis'e into and out of said recess, said holder having the outer surfaces of the arms thereof converging from the base, and the inner surfaces of said arms converging toward said base, a scraper between the arms of said holder, a wedge between said scraper and an arm of said holder for firmly securing the scraper in position, and having wedging surfaces converging towards the rear edge of the scraper, said holder having a recess at the base thereof to permit the insertion of a tool therethrough to loosensaid wedge.

7. A device adapted to be used in a centrifugal machine for removing separated solids from said machine, and including a chute for conveying the solids scraped from said machine, a channelshaped member detachably secured to one Wall of said chute, a scraper between the side arms of said member and having a cutting edge extending beyond the longitudinal edges of said arms, a wedge between saidscraper and an arm of said member, and having the wedging surfaces thereof converging towards the rear edge of the scraper for firmly securing said scraper in position between the arms of said member, said wedge having the thicker edge thereof spaced from the cutting edge of said scraper and between said latter edge and said member.

GUSTAV TER MEER.

cent to the open end of 'said drum and having 

